Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
To separately control driving of a plurality of driven members, it increases the cost of the apparatus to dispose driving units, such as motors, by the number of driven members. Therefore, generally, one driving unit drives the respective driven members. Additionally, a clutch mechanism, which transmits and blocks a driving power, is disposed between the driving unit and the respective driven members.
For example, a drive transmission mechanism, which is used for a driving unit of an image forming apparatus using an electrophotographic method, such as a copier, a printer, and a facsimile, includes a continuous rotation drive train and an intermittent rotation drive train. The continuous rotation drive train continuously rotates the driven members during an image forming operation. The intermittent rotation drive train intermittently rotates the driven members, temporarily halts the operation of the driven members, or stops the driven members alone. Accordingly, an electromagnetic clutch may be built into the intermittent rotation drive train. For example, a certain technique discloses the following driving device. A drive motor and a drive gear are connected with a non-excitation electromagnetic clutch and a drive shaft for the electromagnetic clutch is made of a non-magnetic material.
With another technique discloses that a driving device includes a motor and a plurality of studs (rotation shafts). The studs rotatably support a plurality of respective gears, which are driven by the motor. This driving device includes the plurality of studs whose outer diameters are all different. The inner diameters of the plurality of gears correspond to the outer diameters of the respective studs. This prevents incorrect installation of the gears to the studs.